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At 770 feet, the Oroville Dam is the nation’s highest. At 48 years old, it’s certainly not the nation’s newest dam. It’s important to keep that fact in mind as crews work around the clock in an attempt to reinforce the dam’s damaged emergency spillway before the next round of rains begin later this week in Northern California. The Oroville Dam, like many of the dams, levees, seawalls, and other human efforts to contain nature, is a crucial piece of infrastructure that must be maintained and monitored.

All eyes have been on the crisis at Oroville Dam, but weeks of wet weather have put pressure elsewhere on the network of levees and dams protecting cities and farms in California’s vast Central Valley flood plain. Almost all of the major reservoirs that ring the Valley have filled to the point that officials have cranked up releases to catch water from a storm building up off California’s coast that’s expected to hit Wednesday night.

Inspectors visited Oroville Dam 14 times since 2008 but never considered the integrity of the hillside that eroded below the emergency spillway, leading to a near catastrophe that forced the evacuation of nearly 200,000 people downstream, state records show. The inspections by the state’s Division of Safety of Dams repeatedly mentioned the concrete apron, or weir, at the top of the emergency spillway, and often included photographs of it. “The structure was stable appearing, and the concrete remains sound,” inspectors wrote after their latest visit to the state-run dam in August 2016.